Devices that are either wearable or can be incorporated into point of care diagnostics and/or therapeutics are preferably inexpensive and disposable, as well as lightweight, flexible, and readily manufactured. Achieving such properties, as well as appropriate uses and streamlined manufacture of such devices, are active areas of research. One limitation facing POC device manufacturers is providing power appropriate to the needs of the device, while at the same time minimizing or eliminating the use of expensive or toxic materials.